Field of the Invention
The present disclosure relates to a power supply system, a transportation device, and a power transmission method.
Discussion of the Background
A power supply system of this type, disclosed in Japanese Unexamined Patent Application Publication No. 2015-70726, for example, is known in the related art. Japanese Unexamined Patent Application Publication No. 2015-70726 discloses a system for supplying power to an electric motor for a vehicle by using two energy storage devices, namely, a high-capacity energy storage device having a relatively high capacity and a high-power energy storage device having a relatively high upper limit on power that can be output.
In the disclosed system, the proportion of powers to be output by two energy storage devices are determined in accordance with whether or not an output demand for the two energy storage devices is less than or equal to a predetermined threshold value. One or both of the two energy storage devices provide power to the electric load (electric motor) in the determined proportion.
If the output demand is less than or equal to a predetermined threshold value (hereinafter referred to as “B2 threshold value”) near the output upper limit of the high-capacity energy storage device, power is supplied only from the high-capacity energy storage device to the electric load. If the output demand exceeds the B2 threshold value, power is supplied from both of the two energy storage devices to the electric load.